SUMMARY/ABSTRACT The Data Management Core (DMC) is designed to provide survey research services to the five projects represented in the P01, and to maintain uniformly high standards of data collection, design, and analysis. The DMC will be responsible for: 1. Design and management of data collection for surveys; communication with data providers to ensure uniformity of protocols. 2. Administration of online surveys, including programming of instruments and hosting. 3. Support for instrument development and documentation across projects and surveys, ensuring that data collected provides useful input to substantive research questions and theoretical and simulation studies. 4. Survey data processing, including data cleaning and checking, the construction of weights and pseudo- weights, and the computation of derived variables. 5. Maintenance of a secure repository of data and an efficient secure system that allows the investigators and external researchers to access data. 6. Advice and technical assistance on research design, data collection methods, data analysis, programming for analyses, preparation of analysis plans, papers, and grant applications. 7. Development, testing, and documentation of new methods for data collection and data analysis. The diversity of research designs and the number of data collection sites require a core service to help ensure the integrity and synergy of these projects and the quality of the data. The DMC includes experts in survey sampling, biostatistics and research methods who have extensive backgrounds in research on health behavior and the use of tobacco and its substitutes, as well as data analysts and experts on questionnaire design and databases.